Vertical Flow Wrapper and Method To Produce Packages With A Reduced Gas Content

ABSTRACT

A vertical flow-wrapper, which produces packages, with a frame/housing, at which a form-fill-tube, a longitudinal-sealing means and a cross-sealing means and a cutting means. A method to produce a package from a plane film.

FIELD

The invention relates to improvements of a vertical flow-wrapper, which produces packages, with a frame/housing, at which a form-fill-tube, a longitudinal-sealing means and a cross-sealing means and a cutting means. The invention also relates to a method to produce a package from a plane film.

BACKGROUND

A common method of making packages out of a film web is the use of a vertical flow-wrapper. Such a packaging machine receives a continuous flat sheet, for example a film of plastic material, e.g. a thermoplastic material, which is transported continuously or intermittently and passed downwardly over a form shoulder and is then shaped into a tubular form, i.e. into a film tube, by being wrapped around a vertical form-fill tube of the packaging machine. After being wrapped around the vertical form-fill tube, the film web is longitudinally closed by means of a longitudinally extending seal which is applied to the film especially by heat sealing the lateral/longitudinal margins of the film web or by heat sealing in the vicinity of these margins thereby joining them. This is carried out by so called longitudinal-sealing means. The film tube has conventionally a rectangular, elliptical or a circular cross-sectional area. Conventionally, the film tube is closed by cross-sealing means, preferably in a direction perpendicular to the direction of flow, i.e. transversely. Thereby, individual packages are defined out of the continuous film tube. A product, such as a foodstuff, is introduced by dropping the product through a form-fill tube and into the film tube surrounding the form-fill-tube. During filling, the film tube is transversely open at its upper end, i.e. not cross-sealed. Thereafter and/or simultaneously, the film tube together with the product is moved downwardly and then a top cross-seal is formed above the product and thereby a hermetically closed package produced. As a last step or simultaneously to the application of the top seal, the package is separated from the film tube by cutting means. Besides the product a gas, normally air is also enclosed in the package, which is undesirable.

SUMMARY

The purpose of the invention is therefore to provide a vertical flow-wrapper and a method, which allows to reduce the amount of gas in the package.

The purpose is attained by providing a vertical flow-wrapper, which produces packages, with a frame/housing, at which a form-fill-tube, a longitudinal-sealing means and a cross-sealing means and a cutting means are provided, wherein it further comprises compression means, which at least partially compress each package prior to and/or during providing a cross seal to the package.

The disclosure regarding this embodiment of the present invention also applies to the inventive method and vice versa. Subject matters disclosed regarding the vertical flow-wrapper can be included into the inventive method and vice versa.

The present invention relates to a vertical flow-wrapper with a frame and/or a housing, which receives a continuous flat sheet, e.g. a film of plastic material, e.g. a thermoplastic material, which is transported continuously or intermittently and passed downwardly over a form shoulder and is then shaped into a tubular form, i.e. into a film tube, by being wrapped around a vertical form-fill tube of the packaging machine. After being wrapped around the vertical form-fill tube, the film web is longitudinally closed by means of a longitudinally extending seal which is applied to the film especially by heat sealing the lateral/longitudinal margins of the film web or by heat sealing in the vicinity of these margins thereby joining them. This is carried out by so called longitudinal-sealing means. The film tube has conventionally a rectangular, elliptical or a circular cross-sectional area. Conventionally, the film tube is closed by cross-sealing means, preferably in a direction perpendicular to the direction of flow, i.e. transversely. Thereby, individual packages are defined out of the continuous film tube. A product, such as a foodstuff, is introduced into the film tube by dropping the product through a form-fill tube and into the film tube surrounding the form-fill tube and onto a lower-, first cross seal. During filling the film tube is transversely open at its upper, top end, i.e. not cross-sealed. Thereafter and/or simultaneously, the film tube together with its product is moved downwardly and then a top cross-seal is formed above the product and thereby the hermetically closed package produced. As a last step or simultaneously to the application of the top seal, the package is separated from the film tube by cutting means.

According to the present invention, the inventive vertical flow wrapper further comprises compression means, which at least partially compress each package prior to and/or during providing a cross seal to the package. Due to the compression, gas, e.g. air, within the package is removed, so that the volume of the package and/or the amount of oxygen in the package is reduced.

For the removal of the gas out of the package, the compression means is preferably displaced towards the film tube. Preferably, two, more preferably two parallel compression means are provided, whose distance relative to each other is reduced in order to remove gas out of the package.

Preferably, the compression means are at least partially made from flexible material, preferably a flexible plastic and/or rubber material. A preferred flexible material is silicon. The silicon may have charge to repel the film material. The compression means can be molded and or printed.

Preferably, the compression means are at least partially hollow. The hollow section can be partially or completely filled with a gas and/or a fluid, wherein a gas, preferably air in the hollow section is preferred. The pressure in the hollow part is preferably adjustable. Preferably, the compression means is a bellows.

The compression means may have a round, oval, polygonal, more preferably rectangular or square cross section. Preferably, the cross section is constant over the entire length of the compression means, at least at ambient pressure in the hollow section.

The bellows preferably has a constant wall thickness over its length.

According to a preferred embodiment, the compression means, particularly the hollow section, is connected to a pressure source, which maintains and/or changes an internal pressure within the compression means, particularly within the hollow section, which hence preferably acts as a pressure chamber. The pressure source preferably provides at least temporarily a pressure above and/or below ambient pressure, i.e. the pressure that surrounds the inventive vertical flow wrapper. Preferably, the pressure source is controlled, more preferably such that it is maintained constant within the hollow section, even if the compression means is deformed. The pressure source can be used to alter the shape of the flexible compression means, e.g. increase its size by increasing the pressure in the hollow section or vice versa. Preferably, the cross section of the compression means, preferably the bellows changes with the length of the compression means when the hollow section is pressurized.

Preferably, the compression means is provided parallel to the cross-sealing means.

Preferably, the compression means is provided as a longitudinal bar, which preferably is provided parallel to the cross-sealing means and even more preferably below the cross sealing means relative to the direction of the gravitational force. The bar preferably has a square- or rectangular cross section, which more preferably is constant over its entire length. According to another preferred embodiment, the shape of the compression means at least partially follow the shape of the tip of the pile that the product forms within the package. The compression means can be formed like the tip of an arrow or the segment of an arch.

Preferably, the compression means is attached to the cross-sealing means. In case there are two compression means, preferably one compression means is connected to each side of the cross-sealing means, which as well comprises two parts which co-act during cross sealing. More preferably, each compression means comoves with the respective part of the cross-sealing means. The compression means are preferably directly driven by the cross-sealing means.

Preferably, the surface of the compression means comprises anti-sticking means, preferably one or more bulge(s). The bulges preferably extend out of the surface of the compression means, preferably the bellows. The bulges are preferably provided according to a pattern and or equidistantly. During compression, the bulges are in contact with the film.

Preferably, the compression means can be provided in different heights, i.e. the extension of the compression means in the transport direction of the film. The compression means are preferably exchangeable, preferably depending on the length of the bag, i.e. extension of the bag in the transport direction of the film. Preferably, each compression means comprises an identification, so that the machine can recognize that the correct compression means has been mounted for a specific bag.

The problem is also solved with a method to produce a package from a plane film, which is formed around a form-fill tube into a film tube, whose distal ends are connected by a longitudinal sealing means with a longitudinal seal, wherein a first cross seal is provided at the film tube by cross-sealing means and wherein the film tube is filled with a product before a second cross seal is provided at the film tube and the filled package are separated from the film tube by cutting means, characterized in, that prior and/or during the provision of the second cross seal, a gas is pressed out of the package by compression means.

The disclosure regarding this embodiment of the present invention also applies to the inventive vertical flow wrapper and vice versa. Subject matters disclosed regarding the method can be included into the inventive vertical flow wrapper and vice versa.

This embodiment of the present invention relates to a method to operate a vertical flow-wrapper with a frame and/or a housing, which receives a continuous flat sheet, e.g. a film of plastic material, e.g. a thermoplastic material, which is transported continuously or intermittently and passed downwardly over a form shoulder and is then shaped into a tubular form, i.e. into a film tube, by being wrapped around a vertical form-fill tube of the packaging machine. After being wrapped around the vertical form-fill tube, the film web is longitudinally closed by means of a longitudinally extending seal which is applied to the film especially by heat sealing the lateral/longitudinal margins of the film web or by heat sealing in the vicinity of these margins thereby joining them. This is carried out by so called longitudinal-sealing means. The film tube has conventionally a rectangular, elliptical or a circular cross-sectional area. Conventionally, the film tube is closed by cross-sealing means, preferably in a direction perpendicular to the direction of flow, i.e. transversely. Thereby, individual packages are defined out of the continuous film tube. A product, such as a foodstuff, is introduced into the film tube by dropping the product through a form-fill tube and into the film tube surrounding the form-fill tube and onto a lower-, first cross seal. During filling the film tube is transversely open at its upper, top end, i.e. not cross-sealed. Thereafter and/or simultaneously, the film tube together with its product is moved downwardly and then a top cross-seal is formed above the product and thereby the hermetically closed package produced. As a last step or simultaneously to the application of the top seal, the package is separated from the film tube by cutting means.

According to the present invention, prior and/or during the provision of the second cross seal, a gas is pressed out of the package by compression means. Preferably, the film tube is compressed in the vicinity of the second/upper cross seal and/or in the vicinity of the upper end of the package. Preferably, the package is compressed over its entire extension parallel to the upper cross seal. Preferably, the region of the package above the level of the packaging item, relative to the direction of the gravitational force, is compressed.

The compression means are preferably at least partially made from synthetic and/or rubber material, preferably a flexible material. This material is preferably a material which at least partially comprises silicon. The compression means can be moulded or printed. Preferably, the compression means are mounted to a frame which is preferably connected to the cross sealing means.

Preferably, the compression means are at least partially hollow. This hollow section which is filled with a gas, e.g. air, and/or a fluid, e.g. water, preferably comprises a connection/opening, which can for example be connected to a pressure source, or via which the hollow section can be vented, so that a constant pressure can be maintained in the hollow section, even if the compression means is deformed during operation. Via the pressure connection, the size of the compression means, preferably the volume of the hollow section can be in- and/or increased as needed.

Preferably, the compression means deform during the compression of the package. Preferably the volume of the hollow section becomes smaller, particularly during coaction of two compression means, each connected to one part of the cross sealing means.

Preferably, the pressure in the compression means, particularly in the hollow section, is maintained constant during the compression of the package.

The invention is explained referring to the figures of the attached drawings, by way of non-limiting examples. The explanations apply to the inventive apparatus and the inventive method likewise.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows schematically the vertical flow-wrapper according to the invention.

FIGS. 2 and 3 depict the compression means 10.

FIGS. 4, 5, 5 a show the connection of the compression means to the cross sealing means.

FIG. 5b shows a preferred embodiment of the shape of the compression means.

FIG. 6 shows a combination of a bellow and O-rings as compression means.

FIG. 7 show the package being compressed by the compression means.

In FIG. 1, the vertical flow-wrapper 1 according to the invention is schematically shown. A vertical flow wrapper is a packaging machine, which forms a plane film web into a film tube, which is transported along a form-fill tube 4. Two ends of this film tube are sealed together by a longitudinal sealing means 5. Subsequently, the packaging item is filled into the film tube and a cross-seal is applied to the film tube to close the package. Simultaneously or after applying the cross-seal, the finalized packages are cut off the film tube. The vertical flow wrapper comprises a frame/housing 8, at which a form shoulder 3, a form-fill tube 4 and longitudinal sealing means 5 and cross-sealing means 6 are provided. The vertical flow-wrapper may comprise gusset-forming means to form the bottom and/or the top of each package.

A web of a film 4, especially a weldable plastic film 4, is supplied from a reel 9, which supplies the plane film continuously or intermittently to a form shoulder 3, which shapes the film web into a rather tubular form around a form-fill tube 2. In the context of the present invention, a “tubular form” of the packages or of the film means any cross-sectional form including a circular form or another form, and especially a rectangular or generally a polygonal form. Longitudinal sealing means 5, which are provided downstream from the form shoulder, seal the edges to the film tube together. After sealing, the bottom of the package 7 can be formed by a special bottom forming means, for example gusset-forming means. Finally, cross seals, extending preferably perpendicularly to the direction of flow of the film, are applied, especially by means of cross-sealing means 6. These cross sealing means 6 apply to the package 7 not only an upper/second cross-seal closing the top of the package 7, but these cross-sealing means 6 advantageously also provide, preferably simultaneously a lower/first cross-seal defining the bottom of the subsequent, upstream package 7. The packages 7 produced are separated from one another by a cutting means, which are preferably incorporated into the cross-sealing means 6. Between the application of the bottom- and top-cross-seal of each package, the package is filled with the product, preferably an edible product. Prior and/or during the application of the upper cross seal, the package/film tube is compressed, so that a gas, e.g. air, in the package is removed.

FIGS. 2 and 3 show the compression means 10, which are in the present case provided as a bar, which is preferably provided horizontally and/or parallel to the cross sealing means. The compression means 10 is here depicted as a bellows. The compression means 10 can be connected to a frame 11, preferably by a reversible connection, which can be provided without tools. Two of these compression means co-act during the compression of the package/film tube. The compression means, particularly its jacket 15 is preferably made from a flexible material, such as silicon and/or rubber, particularly the part of the jacket that is contact with and/or faces towards the package/film tube. In the present case, the compression means has a constant cross section over its entire length, which can be square or rectangular, round or oval. FIG. 3 depicts a cut through the compression means according to FIG. 2. It can be seen, that the compression means can, at least partially, be hollow, so that it comprises a hollow section/pressure chamber 14. This hollow section, preferably with a constant cross section over its entire length, preferably comprises a connection 13 which connects the hollow section to a pressure source and/or through which the hollow section can be vented. The hollow section is preferably constant over the entire length of the compression means. The pressure source can be vacuum or excess pressure, so that the volume of the hollow section 14 can be in- and/or decreased. During operation the compression means is preferably compressed. During this compression, the pressure in the hollow section 14 is preferably maintained constant, at least after a certain pressure level has been achieved. The surface of the compression means 10, particularly the part of its jacket that comes in touch with the package/film tube can comprise anti-sticking means 16, like projections 16. The projections are preferably provided as rows, preferably equidistant rows. The projections in the rows are preferably equidistant.

FIGS. 4 and 5 depict the cross sealing/cutting means 6 and the compression means 10 connected to it. The cross sealing/cutting means 6 comprises two members, which are move towards each other to apply the cross seal and away from each other to open the passage, as depicted by the double arrows. One compression means 10 is connected to each member 6 via the frame 11, which comoved together with the members. Connection means 23, here pins 23, are used to connect the compression means 10 the frame 11. In the present case, the frame 11 comprises an array of holes which are preferably arranged equidistantly, so that the compression means 10 can be provided at different distances relative to the cross sealing means 6 and/or the compression means can be exchanged easily, preferably without tools. A scale 17 can be provided to assist attaching the compression means 10 to the frame.

FIG. 5a shows a preferred embodiment to fix the compression means 10 to the cross sealing/cutting means 6 and/or to the frame 11. In the present case fixation means 24, which are provided inside the compression means, here inside the hollow bellow and/or outside fixation means 25 are provided.

In general, a preferred means to fix the compression means 10 to the cross sealing/cutting means 6 and/or to the frame 11 is without tools, preferably utilizing one or more magnets. Preferably, means are provided which fix the compression means 10 to the cross sealing/cutting means 6 and/or to the frame 11 at the desired position.

FIG. 5b shows a preferred embodiment of the shape of the compression means 10. In the present case, the lower end, the end 26 that is directed towards the product is arch-shaped and can preferably follow the pile of a product filled into the bags. The arch may have the contour of the segment of a circle, the segment of an ellipse and/or of a polygon.

FIG. 6 shows a preferred embodiment of the compression means 10, here a combination of a bellows and one or more O-ring(s) 29. In the present case, two poles 27, are provided around which an O-ring is stretched. The O-ring can be held in position by grooves 28, which accommodate the O-ring 29. In the present case, seven O-rings can be provided in the seven parallel grooves 28.

FIG. 7 depict the package 7 and the compression means 10. The bag 7 comprises a longitudinal seal, not depicted, a lower, first cross seal 18 and a second, upper cross seal 19. “Upper” and “lower” relates to the direction of force of gravity. The cross seals 18, 19 are preferably provided perpendicular to the direction of motion of the film tube or package. The cross seals 18, 19 extend into and out of the paper plane. The package is filled with a packing item 21. Preferably, the cross seals extend horizontally during production. The compression means 10 preferably extend also horizontally and are preferably provided such that they compress the region between the second horizontal seal and the packing item, the upper end of the packing item. For the compression of the film-tube/package, the compression means 10 move towards each other as depicted by the arrow 22. The compression preferably takes place before the package 7 is hermetically sealed.

LIST OF REFERENCE SIGNS

1 vertical flow-wrapper

2 form-fill tube

3 form shoulder

4 film, film

5 longitudinal-sealing means

6 cross-sealing- and/or cutting means

7 package, package, pouch

8 frame/housing of the vertical flow-wrapper

9 reel

10 compression means, bellows

11 frame for the compression means 10

12 fastening means

13 pressure connection means

14 hollow section, pressure chamber

15 jacket

16 anti-sticking-means, projection

17 scale

18 first cross seal, lower cross seal

19 second cross seal, top cross seal, upper cross seal

20 transportation direction

21 packaging item

22 compression direction

23 connection means, pin

24 fixation means for the compression means, inside fixation means

25 fixation means for the compression means, outside fixation means

26 lower end of the compression means

27 pole

28 groove

29 compression means, O-ring 

1) A vertical flow-wrapper, which produces packages, comprising: a frame/housing, at which a form-fill-tube, a longitudinal-sealing means, a cross-sealing means and a cutting means are provided, and a compression means, which at least partially compresses each of the packages prior to and/or during providing a cross seal to each of the packages, the compression means is at least partially made from a flexible plastic or rubber material and is at least partially hollow. 2) (canceled) 3) (canceled) 4) The vertical flow wrapper according to claim 1, wherein the compression means is connected to a pressure source, which maintains and/or changes an internal pressure within a hollow section of the compression means. 5) The vertical flow-wrapper according to claim 1, wherein the compression means is provided parallel to the cross-sealing means. 6) The vertical flow-wrapper according to claim 1, wherein the compression means is provided as a longitudinal bar or as the segment of an arch. 7) The vertical flow-wrapper according to claim 1, wherein the a surface of the compression means comprises anti-sticking means and/or one or more bulge(s). 8) The vertical flow-wrapper according to claim 1, wherein the compression means is attached to the cross-sealing means. 9) A method to produce a package from a plane film, which is formed around a form-fill tube into a film tube, whose distal ends are connected by a longitudinal sealing means with a longitudinal seal, wherein a first cross seal is provided at the film tube by cross-sealing means and wherein the film tube is filled with a product before a second cross seal is provided at the film tube and the filled package are separated from the film tube by cutting means, wherein prior and/or during the provision of the second cross seal, a gas is pressed out of the package by compression means, wherein the compression means are at least partially hollow and the pressure in the compression means, can be controlled, or is maintained constant during the compression of the package. 10) The method according to claim 9, wherein the film tube is compressed in a vicinity of the second cross seal. 11) (canceled) 12) The method according to claim 9, wherein the compression means deform during the compression of the package. 13) (canceled) 